Apparatus and method for communication network

ABSTRACT

A control apparatus ( 40 ) is configured to acquire a required end-to-end performance required for an end-to-end path from a first end node to a second end node, and determine each required segment performance required for a respective one of the path segments based on the required end-to-end performance. The control apparatus ( 40 ) is further configured to communicate with a node included in each path segment or communicate with an entity controlling the path segment to enforce a corresponding one of the required segment performances in the path segment. The control apparatus ( 40 ) is further configured to update a required segment performance currently enforced in at least one path segment based on an achievement status of each of the required segment performances in the respective path segments. It is thus, for example, possible to contribute to guaranteeing the required end-to-end performance even when quality of each path segment changes.

This application is a National Stage of International Application No.PCT/JP2017/045067 filed Dec. 15, 2017, claiming priority based onJapanese Patent Application No. 2017-044322 filed Mar. 8, 2017 thedisclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to control over a communication networkand, in particular, to control of a plurality of path segments formingan end-to-end path.

BACKGROUND ART

Providing ultra-low latency services through a radio communicationnetwork has been studied. Ultra-low latency services may include missioncritical communications. For example, the 3rd Generation PartnershipProject (3GPP) has started to work on the standardization for the fifthgeneration mobile communication system (5G), i.e., 3GPP Release 14, in2016 to make it a commercial reality in 2020. The requirements for the5G system architecture include support of mission criticalcommunications.

Ultra-low latency services or mission critical communications include,for example, intelligent transport systems, industrial automation,robotics, the haptic or tactile internet, virtual reality, and augmentedreality. The ultra-low latency services and mission criticalcommunications require end-to-end latency in the order of milliseconds.For example, Non-patent Literature 1 describes that 1-millisecondend-to-end latency is required in tactile internet applications.

Ultra-low latency services and mission critical communications alsorequire reliability. The term “reliability” means a capability ofguaranteeing message transmission within a defined end-to-end latency(i.e., a delay budget, e.g., 1 millisecond).

CITATION LIST Non Patent Literature

-   Non-patent Literature 1: ITU-T Technology Watch Report (August    2014)—The Tactile Internet, [retrieved on 2017-02-27], <URL:    http://www.itu.int/oth/T2301000023/en>

SUMMARY OF INVENTION Technical Problem

A communication path between two end nodes, such as a sensor and anactuator (hereinafter referred to as an end-to-end path) includes two ormore path segments. In order to guarantee predetermined end-to-endlatency, it is required to set a delay target (or delay objective) oneach path segment and enforce the respective delay targets on the pathsegments.

However, it should be noted that quality or a performance of each pathsegment dynamically changes. For example, the two or more path segmentsinclude a radio access network (RAN) segment (i.e., an air interface)between a base station and a terminal, and a wired network segmentbetween the base station and an application server. The quality orperformance (e.g., throughput) of the RAN segment (the air interface)varies due to fading and interference. The quality or performance of thewired network segment may vary depending on processing the load on anetwork entity (e.g., a base station, a router, or a gateway).

Acceptable end-to-end latency is an example of a performance requiredfor the end-to-end path (hereinafter referred to as a requiredend-to-end performance). In another example, the required end-to-endperformance may be end-to-end throughput.

One of the objects to be attained by embodiments disclosed herein is toprovide an apparatus, a method, and a program that contribute toguaranteeing a required end-to-end performance even when quality of eachpath segment changes. It should be noted that the above-described objectis merely one of the objects to be attained by the embodiments disclosedherein. Other objects or problems and novel features will be madeapparent from the following description and the accompanying drawings.

Solution to Problem

In a first aspect, a control apparatus includes a memory, and at leastone processor coupled to the memory and configured to execute aplurality of modules. The modules include an acquisition module, acontrol module, and an enforcement module. The acquisition module isconfigured to acquire a required end-to-end performance required for anend-to-end path from a first end node to a second end node. Theend-to-end path includes the first and second end nodes and at least oneintermediate node, and the end-to-end path includes a plurality of pathsegments. The control module is configured to determine each requiredsegment performance required for a respective one of the path segmentsbased on the required end-to-end performance. The enforcement module isconfigured to communicate with a node included in each path segment orcommunicate with an entity controlling the path segment to enforce acorresponding one of the required segment performances in the pathsegment. The control module is further configured to update a requiredsegment performance currently enforced in at least one path segmentbased on an achievement status of each of the required segmentperformances in the respective path segments.

In a second aspect, a method performed by a control apparatus includes:

(a) acquiring a required end-to-end performance required for anend-to-end path from a first end node to a second end node, theend-to-end path including the first and second end nodes and at leastone intermediate node, the end-to-end path including a plurality of pathsegments;(b) determining each required segment performance required for arespective one of the path segments based on the required end-to-endperformance;(c) communicating with a node included in each path segment orcommunicating with an entity controlling the path segment in order toenforce a corresponding one of the required segment performances in thepath segment, and(d) updating a required segment performance currently enforced in atleast one path segment based on an achievement status of each of therequired segment performances in the respective path segments.

In a third aspect, a program includes a set of instructions (softwarecodes) that, when loaded into a computer, causes the computer to performa method according to the above-described second aspect.

Advantageous Effects of Invention

According to the above-described aspect, it is possible to provide anapparatus, method, and program that contribute to guaranteeing arequired end-to-end performance even when quality of each path segmentchanges.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a configuration example of a communication networkaccording to a first embodiment;

FIG. 2 shows an example of an end-to-end path;

FIG. 3 shows an example of an end-to-end path;

FIG. 4 shows an example of an end-to-end path;

FIG. 5 shows an example of an end-to-end path;

FIG. 6 is a flowchart showing an example of operations performed by acontrol apparatus according to the first embodiment;

FIG. 7 is a block diagram showing a configuration example of a controlapparatus; and

FIG. 8 is a block diagram showing a configuration example of anintermediate node.

DESCRIPTION OF EMBODIMENTS

Specific embodiments will be described hereinafter in detail withreference to the drawings. The same or corresponding elements aredenoted by the same symbols throughout the drawings, and duplicatedexplanations are omitted as necessary for the sake of clarity.

First Embodiment

FIG. 1 shows a configuration example of a communication networkaccording to some embodiments including this embodiment. In the exampleshown in FIG. 1 , the communication network includes an end node 10,intermediate nodes 20A and 20B, and an end node 30. An end-to-end path100 is a communication path from the end node 10 to the end node 30. Theend node 10 may be referred to as a sender end node while the end node30 may be referred to as a receiver end node.

In the cases of the tactile internet and industrial automation, the endnode 10 may be a computer installed in a sensor and the end node 30 maybe a computer installed in an actuator. In the case of an IntelligentTransportation System (ITS), both of the end nodes 10 and 30 may becomputers installed in automobiles. Alternatively, one of the end nodes10 and 30 may be a computer installed in an automobile while the otherend node may be an ITS application server.

The end-to-end path 100 is composed of two or more path segments 110.Accordingly, the end-to-end path 100 includes at least one intermediatenode 20. In the example shown in FIG. 1 , the end-to-end path 100 isdivided into three path segments 110A, 110B and 110C. The path segment110A is a communication path from the (sender) end node 10 to theintermediate node 20A. The path segment 110B is a communication pathfrom the intermediate node 20A to the intermediate node 20B. The pathsegment 110C is a communication path from the intermediate node 20B tothe (receiver) end node 30.

The end-to-end path 100 is a communication path in the application layerand transfers application-layer messages. In other words, the end-to-endpath 100 transfers an application-layer packet flow. Both of the endnodes 10 and 30 support an application-layer protocol and processapplication-layer messages.

Further, at least one intermediate node 20 may support theapplication-layer protocol and process application-layer messages. Thatis, a communication event (or a communication transaction) that isperformed on the end-to-end path 100 may include two or moreapplication-layer communications.

For example, in the above-described case of the haptic internet andindustrial automation, at least one intermediate node 20 may be acontrol/steering server that controls the actuator (i.e., the end node30) on the basis of sensing data received from the sensor (i.e., the endnode 10). In the case of the Intelligent Transportation System (ITS), atleast one intermediate node 20 may be an ITS server that receives amessage or data from an automobile (i.e., the end node 10) and controlsthe automobile or another automobile (i.e., the end node 30).

Additionally or alternatively, some or all of the one or moreintermediate nodes 20 may support the network layer (i.e., Layer 3,e.g., the Internet Protocol (IP) layer) and transfer a packet(s)containing an application-layer message between the end nodes 10 and 30.For example, each intermediate node 20 may be an IP router or a gateway.

Additionally or alternatively, at least one intermediate node 20 may bea RAN node (e.g., base station, eNodeB, or Radio Network Controller(RNC)) that communicates with the end node 10 or 30 through an airinterface.

FIGS. 2 to 5 show several specific examples of the end-to-end path 100.In the example shown in FIG. 2 , the end-to-end path 100 is acommunication path from a radio terminal (User Equipment (UE)) 210 to anapplication server 270. Accordingly, the UE 210 corresponds to the(sender) end node 10 and the application server 270 corresponds to the(receiver) end node 30.

The end-to-end path 100 shown in FIG. 2 is divided into two pathsegments 110A and 110B by a RAN node 230. The RAN node 230 correspondsto the intermediate node 20. The path segment 110A in FIG. 2 is acommunication path from the UE 210 to the RAN node 230 through a RAN 220(i.e., an uplink air interface). The path segment 110B in FIG. 2 is acommunication path from the RAN node 230 to the application server 270.The path segment 110B in FIG. 2 passes through a core network 240, acore network (CN) gateway 250, and a Packet Data Network (PDN) 260. Thecore network 240 is for example an Evolved Packet Core (EPC) or aUniversal Mobile Telecommunications System (UMTS) packet core, while theCN gateway 250 is for example a PDN Gateway (PGW) or a Gateway GPRSSupport Node (GGSN).

In the example shown in FIG. 3 , the end-to-end path 100 is a round-trippath that starts from a UE 310, passes through an application server370, and returns to the UE 310. Accordingly, the UE 310 corresponds toboth the (sender) end node 10 and the (receiver) end node 30.

The end-to-end path 100 shown in FIG. 3 is divided into four pathsegments 110A, 110B, 110C and 110D by a RAN node 330 and an applicationserver 370. The path segment 110A in FIG. 3 is a communication path froma UE 310 to the RAN node 330 through a RAN 320 (i.e., an uplink airinterface). The path segment 110B in FIG. 3 is a communication path fromthe RAN node 330 to the application server 370. The path segment 110C inFIG. 3 is a communication path from the application server 370 to theRAN node 330. The path segments 110B and 110C in FIG. 3 pass through acore network 340, a CN gateway 350, and a PDN 360. The path segment 110Din FIG. 3 is a communication path from the RAN node 330 to the UE 310through the RAN 320 (i.e., a downlink air interface).

The example shown in FIG. 4 is a modified example of the example shownin FIG. 3 . That is, in the example shown in FIG. 4 , the end-to-endpath 100 starts from the UE 310, passes through the application server370, and reaches a UE 490. Accordingly, the UE 310 corresponds to the(sender) end node 10 and the UE 490 corresponds to the (receiver) endnode 30. The path segment 110C in FIG. 4 is a communication path fromthe application server 370 to a RAN node 480. The path segment 110D inFIG. 4 is a communication path from the RAN node 480 to the UE 490through the RAN 320 (i.e., downlink air interface). The RAN node 480 maybe identical to the RAN node 330.

The examples shown in FIG. 5 relates to Mobile Edge Computing (MEC). TheMEC offers, to application developers and content providers,cloud-computing capabilities and an information technology (IT) serviceenvironment in the RAN in close proximity to mobile subscribers. Thisenvironment provides ultra-low latency and high bandwidth as well asdirect access to radio network information (subscriber's location, cellload etc.) that can be leveraged by applications and services. The MECis based on a virtualized platform, similar to Network FunctionVirtualization (NFV). While NFV focuses on network functions, MECenables applications to be run at the edge of the network.

A mobile edge cloud 540 provides an application server 550 withcomputing resources, storage capacity, and an interface with a RAN. Morespecifically, the mobile edge cloud 540 provides a hosting environmentfor applications by providing Infrastructure as a Service (IaaS)facilities or Platform as a Service (PaaS) facilities. That is, theapplication server 550 may be an application (hereinafter referred to asan MEC application) hosted on a server (hereinafter referred to as anMEC server) in the mobile edge cloud 540. The mobile edge cloud 540 (orthe MEC server) can also be referred to as an Internet of Things (IoT)service enabler.

The end-to-end path 100 shown in FIG. 5 is divided into four pathsegments 110A, 110B, 110C and 110D by a RAN node 530 and the applicationserver 550. The path segment 110A in FIG. 5 is a communication path froma UE 510 to the RAN node 530 through a RAN 520 (i.e., an uplink airinterface). The path segment 110B in FIG. 5 is a communication path fromthe RAN node 530 to the application server 550 arranged in the MECenvironment. The path segment 110C in FIG. 5 is a communication pathfrom the application server 55 to the RAN node 530. The path segments110B and 110C in FIG. 5 pass through the mobile edge cloud 540. The pathsegment 110D in FIG. 5 is a communication path from the RAN node 530 tothe UE 510 through the RAN 520 (i.e., a downlink air interface).

Referring back to FIG. 1 , a controller 40 shown in FIG. 1 is a controlapparatus configured to control a plurality of path segments forming anend-to-end path. In order to control each path segment 110, thecontroller 40 communicates with at least one node included in the pathsegment 110 or communicates with an entity that manages the path segment110. For example, the controller 40 may communicate with the RAN node230 to control the path segment 110A (i.e., a RAN segment) shown in FIG.2 . The controller 40 may communicate with at least one of the RAN node230, the CN gateway 250, and the application server 270, to control thepath segment 110B (i.e., a wired network segment) shown in FIG. 2 .Additionally or alternatively, the controller 40 may communicate with acontrol entity (e.g., a Service Capability Exposure Function (SCEF) or aPolicy and Charging Rules Function (PCRF)) in the core network 240 tocontrol the path segment 110B shown in FIG. 2 . That is, althoughrespective connection relations between the controller 40 and the fournodes 10, 20A, 20B and 30 included in the end-to-end path 100 are shownin FIG. 1 , the controller 40 may communicate only with some of thesefour nodes.

The controller 40 may be a single computer system or may be(distributed) computer systems. In some implementations, the controller40 may be arranged in a core network (e.g., the core network 240 or 340)or may be arranged in a PDN (e.g., the PDN 260 or 360). For example, thecontroller 40 may be arranged in a control node (e.g., an SCEF) withinthe core network. In some implementations, the controller 40 may bearranged in the mobile edge cloud 540 (e.g., an MEC server or an IoTservice enabler) shown in FIG. 5 . In some implementations, thecontroller 40 may be arranged in one of the nodes included in theend-to-end path 100 (e.g., the end node 10, one of the intermediatenodes 20, or the end node 30).

The following describes operations performed by the controller 40 withreference to FIG. 6 . FIG. 6 is a flowchart showing a process 600 thatis an example of operations performed by the controller 40. In Step 601,the controller 40 acquires a required end-to-end performance requiredfor the end-to-end path 100. The required end-to-end performance may beacceptable end-to-end latency (i.e., an acceptable delay budget, e.g., 1millisecond, 10 milliseconds, or 100 milliseconds). Alternatively, therequired end-to-end performance may be end-to-end throughput.

In some implementations, the controller 40 may read a value of therequired end-to-end performance stored in a memory or a storage.Alternatively, the controller 40 may communicate with a subscriberinformation management server (e.g., a Home Subscriber Server (HSS)) andacquire a value of the required end-to-end performance from thesubscriber information management server. Alternatively, the controller40 may acquire a value of the required end-to-end performance from theend node 10 (e.g., the UE 210, 310 or 510), from the end node 30 (e.g.,the application server 270 or the UE 490), or from one of theintermediate nodes 20 (e.g., the application server 370 or 550).Alternatively, the controller 40 may acquire a value of the requiredend-to-end performance from another server (e.g., the mobile edge cloud540).

In Step 602, the controller 40 determines respective required segmentperformances required for the path segments 110 based on the requiredend-to-end performance. Each required segment performance may be a delaytarget (e.g., 0.5 milliseconds, 1 millisecond, or 10 milliseconds) foreach path segment 110. The delay target for each path segment 110 canalso be referred to as an acceptable (segment) delay or an acceptablemaximum (segment) delay. Alternatively, each required segmentperformance may be a throughput target for each path segment 110.

The controller 40 may acquire other parameters needed to calculate eachrequired segment performance from a memory or another node. These otherparameters may include, for example, the size of data to be sent in onecommunication event in each path segment and the maximum throughput ofeach path segment. The controller 40 may acquire these other parametersalong with the required end-to-end performance in Step 601.

In Step 603, the controller 40 communicates with a node included in eachpath segment 110 or communicates with an entity controlling the pathsegment 110 to enforce a corresponding one of the required segmentperformances in the path segment 110. In other words, the controller 40requests or instructs a node (or an entity) related to each path segment110 to enforce the corresponding required segment performance in thispath segment 110. The enforcement of the required segment performanceaffects, for example, one or both of packet scheduling and packetqueuing performed by one of the end nodes and the intermediate nodes(e.g., a UE, a RAN node, a gateway, or a router). In order to achievethe enforced required segment performance, the end node or theintermediate node controls the treatment (e.g., priority) in one or bothof the scheduling and the queuing of a packet flow related to thecorresponding path segment or another packet flow.

For example, a RAN node (e.g., radio base station, eNodeB, or RNC) has aMAC scheduler that performs packet scheduling (i.e., Medium AccessControl (MAC) scheduling). In some implementations, the MAC scheduleruses a scheduling metric based on the Earliest Deadline First (EDF)approach (i.e., EDF metric). The EDF metric is in proportion to thereciprocal of the difference between the delay threshold and the head ofline delay. The head of line delay means a delay of the first packet ofuser's pending packets to be transmitted. In order to achieve theenforced required segment performance, the MAC scheduler may change thedelay threshold used for the calculation of the EDF metric for a packetflow related to the corresponding path segment or another packet flow.

For example, a gateway (e.g., PGW or SGSN) and an IP router may controlthe treatment (e.g., priority) in one or both of classification andscheduling for a packet flow related to the path segment or anotherpacket flow so as to achieve the enforced required segment performance.In some implementations, the gateway and the IP router may change aclass of a packet flow related to the path segment in order to increasethe priority of the packet flow. Additionally or alternatively, thegateway and the IP router may change a Weight Fair Queuing (WFQ) weightapplied to a queue that the packet flow related to the path segment isto be stored in.

In Step 604, the controller 40 updates the required segment performancecurrently enforced in at least one path segment based on an achievementstatus of each of the required segment performances in the respectivepath segments 110. For example, the controller 40 may relax a newrequired segment performance for a path segment 110 that has not beenable to achieve the currently enforced required segment performance.Additionally or alternatively, the controller 40 may tighten a newrequired segment performance for a path segment 110 that has achievedthe currently enforced required segment performance.

More specifically, the controller 40 may operate as follows. Firstly,the controller 40 relaxes a new required segment performance (e.g.,increases an acceptable segment delay) for a path segment 110 that hasnot been able to achieve the currently enforced required segmentperformance. Next, in order to compensate for the insufficientperformance (e.g., the increase in delay) caused by the relaxation ofthe required segment performance, the controller 40 tightens a newrequired segment performance (e.g., reduces an acceptable segment delay)for another path segment 110.

In Step 604, the controller 40 may acquire a monitored performanceparameter of each of the path segments 110 and determine whether each ofthe required segment performances has been achieved based on theacquired performance parameter. The performance parameter may be, forexample, effective throughput or a measured value of a time required totransmit unit data.

The controller 40 repeats Steps 603 and 604, thereby dynamicallyadjusting each required segment performance based on the achievementstatus of each required segment performance. The controller 40 thus cancontribute to guaranteeing the required end-to-end performance even whenquality of each path segment 110 changes.

The following describes an example of a detailed algorithm performed inSteps 602 and 604 in FIG. 6 . In this example, the required end-to-endperformance is an end-to-end delay budget and the required segmentperformance for each path segment is an acceptable segment delay.Parameters shown below are used:

-   -   Required end-to-end performance: End-to-end delay budget        (E2E_Delay_Budget);    -   Required segment performance for i-th path segment: Acceptable        segment delay (Max_Delay_i);    -   The Size of data to be sent in i-th path segment in one        communication event: Data_Size_i;    -   The Maximum achievable throughput of i-th path segment:        Achievable_Throughput_i;    -   Monitored effective throughput of i-th path segment:        Effective_Throughput_i;    -   Relief factor for i-th path segment: Relief_Factor_i;    -   Increment of the relief factor: Delta_Increment;    -   Decrement of the relief factor: Delta_Decrement; and    -   The Maximum value of the relief factor: Max_Relief_Factor.

In Step 602 in FIG. 6 , the controller 40 determines the initial valueof the acceptable segment delay of each path segment 110 according tothe following Expression (1):

$\begin{matrix}{{{Max\_ Delay}{\_ i}} = {{\frac{\frac{{Data\_ Size}{\_ i}}{{Achievable\_ Throughput}{\_ i}}}{\sum\limits_{x = 1}^{n}\frac{{Data\_ Size}{\_ x}}{{Achievable\_ Throughput}{\_ x}}} \cdot E}\; 2{E\_ Delay}{{\_ Budget}.}}} & (1)\end{matrix}$

The maximum achievable throughput of each path segment may be acquiredfrom each node. The maximum achievable throughput of each path segmentmay be derived from a parameter reported from each node. For example,the maximum achievable throughput of a RAN segment may be derived from aChannel Quality Indicator (CQI) value of the UE (e.g., the UE 210) andthe total throughput of the RAN node. In order to obtain the maximumthroughput (hereinafter referred to as the first maximum throughput)from the CQI value of the UE, the controller 40 may refer to a table inwhich a relation between CQI values and the maximum throughput that canbe achieved when all the radio resources (e.g., all the resource blocks)of the RAN node are used. However, when the first throughput exceeds themaximum achievable throughput that can be achieved by the remainingresources of the RAN node (hereinafter referred to as the second maximumthroughput), the controller 40 may use the second maximum throughputinstead of the first maximum throughput. The second maximum throughputmay be obtained by subtracting the sum of throughputs of UEs currentlyconnected to the RAN node from the total throughput of the RAN node. Thesum of throughputs of UEs currently connected to the RAN node may be avalue that is obtained by multiplying the number of UEs currentlyconnected to the RAN node by the maximum throughput corresponding to anaverage CQI value of these UEs.

By using the Expression (1), even when the respective sizes of data tobe transmitted in the path segments differ from one another, theacceptable segment delays according to the respective sizes of data tobe transmitted can be assigned to the path segments in an equitablemanner. Further, the acceptable segment delays according to therespective maximum achievable throughputs of the path segments can beassigned to the path segments.

In Step 604 in FIG. 6 , the controller 40 determines whether thefollowing Expression (2) is satisfied based on the observed effectivethroughput of each path segment i20:

$\begin{matrix}{\frac{{Data\_ Size}{\_ i}}{{Effective\_ Throughput}{\_ i}} \leq {{Max\_ Delay}{{\_ i}.}}} & (2)\end{matrix}$

When the Expression (2) is satisfied for the i-th path segment, thecontroller 40 determines that the required segment performance currentlyenforced in this path segment has been achieved. On the other hand, whenthe Expression (2) is not satisfied for the i-th path segment, thecontroller 40 determines that the required segment performance currentlyenforced in this path segment has not been achieved.

Further, in Step 604 in FIG. 6 , the controller 40 adds the decrementDelta_Decrement to the relief factor Relief_Factor_i of an inappropriatepath segment that has been determined not to have achieved the currentrequired segment performance. However, the value of the relief factorRelief_Factor_i should not be greater than the maximum valueMax_Relief_Factor. Then, the controller 40 obtains a new requiredsegment performance (i.e., acceptable segment delay) of theinappropriate path segment according to the following Expression (3):New_Max_Delay_i=Current_Max_Delay_i·Relief_Factor_i  (3).

Meanwhile, the controller 40 determines a new required segmentperformance (i.e., acceptable segment delay) of an appropriate pathsegment that has been determined to have achieved the current requiredsegment performance according to the following Expression (4):

$\begin{matrix}{{{{New\_ Max}{\_ Delay}{\_ i}} = {{{Current\_ Max}{\_ Delay}{\_ i}} - \frac{{Total\_ added}{\_ delay}}{{N\_ inappropriate}{\_ segments}}}},} & (4)\end{matrix}$where, “N_inappropriate_segments” is the total number of inappropriatepath segments that have been determined not to have achieved theirrespective current required segment performances, and“Total_exempted_delay” is the sum of acceptable segment delays whichhave been added to these inappropriate path segments (i.e., by whichthey have been relaxed) according to the Expression (3).

By using the Expression (3), the controller 40 can relax a new requiredsegment performance (i.e., increase an acceptable segment delay) for apath segment 110 that has not been able to achieve the currentlyenforced required segment performance. Further, by using the Expression(4), the controller 40 can tighten a new required segment performance(i.e., reduce an acceptable segment delays) for other path segments 110so as to compensate for the insufficient performance (e.g., the increasein delay) caused by the relaxation of the required segment performance.

Second Embodiment

This embodiment provides a modified example of the procedure forupdating a required segment performance described in the firstembodiment. Configuration examples of a communication network accordingto this embodiment are similar to those shown in FIGS. 1 to 5 .

The controller 40 according to this embodiment performs the procedurefor updating a required segment performance in Step 604 in FIG. 6 asfollows. When the difference between the currently enforced requiredsegment performance and the new required segment performance exceeds athreshold, the controller 40 enforces the new required segmentperformance in the corresponding path segment 110. On the other hand,when the difference does not exceed the threshold, the controller 40refrains from enforcing the new required segment performance in thecorresponding path segment 110.

Frequent updating of the required segment performance may cause anincrease in the load on each node (e.g., an end node or an intermediatenode). The controller 40 according to this embodiment refrains fromupdating the required segment performance when the difference betweenthe currently enforced required segment performance and the new requiredsegment performance is smaller than the threshold. Accordingly, thecontroller 40 according to this embodiment can contribute to preventingthe load on each node from increasing due to the frequent updating ofthe required segment performance.

Third Embodiment

The procedure for updating a required segment performance described inthe above embodiments may be modified as appropriate. This embodimentprovides several modified examples of the procedure for updating arequired segment performance. Configuration examples of a communicationnetwork according to this embodiment are similar to those shown in FIGS.1 to 5 .

For example, the controller 40 may just tighten a new required segmentperformance for a path segment 110 that has achieved the currentlyenforced required segment performance without relaxing a new requiredsegment performance for a path segment 110 that has not been able toachieve the currently enforced required segment performance.

Additionally or alternatively, the controller 40 may update a requiredsegment performance of a RAN segment as follows. When a required segmentperformance for a RAN segment of a certain UE (hereinafter referred toas the first UE) has not been achieved, the controller 40 may relax arequired segment performance for a RAN segment of another UE(hereinafter referred to as the second UE) that is connected to the RANnode to which the first UE is also connected. It is expected that radioresources that can be allocated to the first UE will increase byrelaxing the required segment performance of the second UE (e.g.,increasing the delay target (the acceptable delay) or lowering thethroughput target). The above-described operation thus can expedite (orfacilitate) the achievement of the required segment performance (e.g.,the delay target (the acceptable delay) or the throughput target) forthe RAN segment of the first UE.

Similarly, the controller 40 may update a required segment performanceof a wired network segment as follows. When a required segmentperformance for a wired network segment of a certain UE (hereinafterreferred to as the first UE) has not been achieved, the controller 40may relax a required segment performance for a wired network segment ofanother UE (hereinafter referred to as the second UE). It is expectedthat processing resources that can be used for a packet flow of thefirst UE will increase by relaxing the required segment performance ofthe second UE (e.g., increasing the delay target (the acceptable delay)or lowering the throughput target). Alternatively, it is expected thatthe priority of the packet flow of the first UE will relatively goes up.The above-described operation thus can expedite (or facilitate) theachievement of the required segment performance (e.g., the delay target(the acceptable delay) or the throughput target) for the wired networksegment of the first UE.

Fourth Embodiment

This embodiment provides several examples of network resource allocationperformed by an intermediate node 20 (e.g., a RAN node or a gateway).Configuration examples of a communication network according to thisembodiment are similar to those shown in FIGS. 1 to 5 .

Allocation of network resources (e.g., radio resources or communicationbandwidth) to a plurality of radio terminals (UEs) is describedhereinafter. The intermediate node 20, which performs network resourceallocation, reduces resources allocated to a first UE(s) and thenallocates the surplus resources obtained by the reduction to a secondUE(s). The first UE(s) is a UE(s) that has been allocated resourceslarger than those required to achieve the required segment performance(e.g., the delay target or the throughput target) determined by thecontroller 40. Meanwhile, the second UE(s) is a UE(s) that has beenallocated resources smaller than those required to achieve the requiredsegment performance.

In other words, the intermediate node 20 compares an amount of resourcesallocated to each UE with an amount of resources needed to achieve therequired segment performance for this UE, and determines whether theamount of resources allocated to each UE is appropriate, excessive, orinsufficient. Then, the intermediate node 20 takes away the surplus (orexcess) resources from a UE(s) having them and allocates these resourcesto a UE(s) that does not have sufficient resources. In this way, theintermediate node 20 reduces the number of UEs having surplus (orexcess) resources and the number of UEs that do not have sufficientresources. The intermediate node 20 thus increases the number of UEsthat have been allocated appropriate amounts of resources necessary andenough to achieve the required segment performance as much as possible.

When there is a UE(s) that does not have sufficient resources even afterperforming the above-described step, the intermediate node 20 mayre-allocate bandwidth that has been allocated to one or more UEs forwhich the shortage of resources is relatively large to one or more UEsfor which the shortage of resources is relatively small. That is, theintermediate node 20 preferentially helps UEs having a relatively smallshortage of resources over UEs having a relatively large shortage ofresources, in order to increase the number of UEs that can achieve theirrespective required segment performances (e.g., the delay targets or thethroughput targets) as much as possible,

When there is a UE(s) that does not have sufficient resources even afterperforming the above two steps, the intermediate node 20 may allocateresources to this UE(s) in a best effort manner.

As understood from the above description, the method for allocatingnetwork resources according to this embodiment can contribute toincreasing the number of UEs that have been allocated appropriateresources necessary and enough to achieve their required segmentperformances as much as possible. In other words, the method forallocating network resources according to this embodiment can contributeto increasing the number of UEs that can achieve their required segmentperformances.

Fifth Embodiment

This embodiment provides a modified example of operations performed bythe controller 40. Configuration examples of a communication networkaccording to this embodiment are similar to those shown in FIGS. 1 to 5.

The controller 40 according to this embodiment monitors atraffic-related parameter. The traffic-related parameter affects thedetermination of at least one required segment performance for achievingthe required end-to-end performance. The traffic-related parameter maybe, for example, the size of data to be sent in one communication eventin each path segment 110. Additionally or alternatively, thetraffic-related parameter may include at least one of a data rate percommunication event and an interval between communications in thecommunication event. That is, the traffic-related parameter may be aparameter that relates to the pattern of a traffic flow and changes asthe transmission data size or the data rate per communication eventchanges.

In some implementations, the controller 40 may acquire a configured ormeasured value of the traffic-related parameter from the end node 10 or30. Additionally or alternatively, the controller 40 may acquire ameasured value of the traffic-related parameter from at least oneintermediate node 20 that takes part in the transfer of the trafficflow. Additionally or alternatively, the controller 40 may acquire aconfigured or measured value of the traffic-related parameter fromanother control entity.

In addition, the controller 40 according to this embodiment updates arequired segment performance for each path segment 110 that is affectedby a change in the traffic-related parameter in order to compensate forthe change in the traffic-related parameter.

The controller 40 thus can compensate for the change in thetraffic-related parameter and hence contribute to stabilizing control ofeach path segment to achieve the required end-to-end performance.

Sixth Embodiment

This embodiment provides a modified example of operations performed bythe intermediate node 20. Configuration examples of a communicationnetwork according to this embodiment are similar to those shown in FIGS.1 to 5 .

The controller 40 according to this embodiment monitors atraffic-related parameter. The definition of the traffic-relatedparameter is similar to that described in the fifth embodiment. In someimplementations, the intermediate node 20 may acquire a configured ormeasured value of the traffic-related parameter from the end node 10 or30. Additionally or alternatively, the intermediate node 20 may measurethe traffic-related parameter by itself.

Further, the intermediate node 20 according to this embodiment updates arequired segment performance for each path segment 110 that is affectedby a change in the traffic-related parameter in order to compensate forthe change in the traffic-related parameter.

The intermediate node 20 thus can compensate for the change in thetraffic-related parameter and hence contribute to stabilizing control ofeach path segment in order to achieve the required end-to-endperformance.

Lastly, configuration examples of the controller 40 and the intermediatenode 20 according to the above embodiments will be described. FIG. 7 isa block diagram showing a configuration example of the controller 40.Referring to FIG. 7 , the controller 40 includes a network interface701, a processor 702, and a memory 703. The network interface 701 isused to communicate with network entities (e.g., end nodes, intermediatenodes, a UE, a RAN node, a CN node, and an application server). Thenetwork interface 701 may include, for example, a network interface card(NIC) conforming to the IEEE 802.3 series.

The processor 702 loads software (computer program(s)) from the memory703 and executes the loaded software, thereby performing processing ofthe controller 40 described in the above embodiments. The processor 702may be, for example, a microprocessor, an MPU, or a CPU. The processor702 may include a plurality of processors.

The memory 703 is composed of a volatile memory and a nonvolatilememory. The memory 703 may include a plurality of memory devices thatare physically independent from each other. The volatile memory is, forexample, a Static Random Access Memory (SRAM), a Dynamic RAM (DRAM), ora combination thereof. The non-volatile memory is, for example, a maskRead Only Memory (MROM), an Electrically Erasable Programmable ROM(EEPROM), a flash memory, a hard disc drive, or any combination thereof.The memory 703 may include a storage located apart from the processor702. In this case, the processor 702 may access the memory 703 throughan I/O interface (not shown).

In the example shown in FIG. 7 , the memory 703 is used to storesoftware modules including an acquisition module 704, a control module705, and an enforcement module 706. The processor 702 loads the softwaremodule from the memory 703 and executes the loaded software module,thereby performing the processing of the controller 40 described by inthe above embodiments.

The processor 702 can load and execute the acquisition module 704,thereby performing, for example, the processing in Step 601 in FIG. 6 .The processor 702 can load and execute the control module 705, therebyperforming, for example, the processing in Steps 602 and 604 in FIG. 6 .The processor 702 can load and execute the enforcement module 706,thereby performing, for example, the processing in Step 603 in FIG. 6 .

FIG. 8 is a block diagram showing a configuration example of theintermediate node 20 according to the above embodiments. In the exampleshown in FIG. 8 , the intermediate node 20 is an RAN node. Referring toFIG. 8 , the intermediate node 20 includes an RF transceiver 801, anetwork interface 803, a processor 804, and a memory 805. The RFtransceiver 801 performs analog RF signal processing to communicate withthe UE 1. The RF transceiver 801 may include a plurality oftransceivers. The RF transceiver 801 is connected to an antenna 802 andthe processor 804. In some implementations, the RF transceiver 801receives modulated symbol data (or OFDM symbol data) from the processor804, generates a transmission RF signal, and supplies the generatedtransmission RF signal to the antenna 802. Further, the RF transceiver801 generates a baseband reception signal based on a reception RF signalreceived by the antenna 802 and supplies this signal to the processor804.

The network interface 803 is used to communicate with a network node(e.g., a MME or an S/P-GW) and the controller 40. The network interface803 may include, for example, a network interface card (NIC) conformingto the IEEE 802.3 series.

The processor 804 performs digital baseband signal processing (i.e.,data-plane processing) and control-plane processing for radiocommunication. For example, in the case of LTE or LTE-Advanced, thedigital baseband signal processing performed by the processor 804 mayinclude signal processing of the PDCP layer, RLC layer, MAC layer, andPHY layer. Further, the control-plane processing performed by theprocessor 804 may include processing of the Si protocol, RRC protocol,and MAC CEs.

The processor 804 may include a plurality of processors. For example,the processor 804 may include a modem-processor (e.g., DSP) thatperforms the digital baseband signal processing, and aprotocol-stack-processor (e.g., CPU or MPU) that performs thecontrol-plane processing.

The memory 805 is composed of a volatile memory and a nonvolatilememory. The volatile memory is, for example, an SRAM, a DRAM, or acombination thereof. The nonvolatile memory is, for example, an MROM, aPROM, a flash memory, a hard disk drive, or a combination thereof. Thememory 805 may include a storage located apart from the processor 804.In this case, the processor 804 may access the memory 805 through thenetwork interface 803 or an I/O interface (not shown).

The memory 805 may store one or more software modules (or computerprograms) including instructions and data to perform processing by theintermediate node 20 described in the above embodiments. In someimplementations, the processor 804 may be configured to load thesoftware module from the memory 805 and execute the loaded softwaremodule, thereby performing the processing of the intermediate node 20described in the above embodiments with reference to the drawings.

In the example shown in FIG. 8 , the memory 805 is used to store one ormore software modules 806. The one or more software modules 806 includeinstructions and data for performing the processing by the intermediatenode 20 described in the above embodiments. The processor 802 can loadthese software modules 806 from the memory 803 and execute the loadedsoftware modules, thereby performing the processing of the intermediatenode 20 described in the above embodiments.

As described above with reference to FIGS. 7 and 8 , each of theprocessors included in the controller 40 and the intermediate node 20 inthe above embodiment may be configured to execute one or more programsincluding a set of instructions to cause a computer to perform analgorithm described above with reference to the drawings. These programsmay be stored in various types of non-transitory computer readable mediaand thereby supplied to computers. The non-transitory computer readablemedia includes various types of tangible storage media. Examples of thenon-transitory computer readable media include a magnetic recordingmedium (such as a flexible disk, a magnetic tape, and a hard diskdrive), a magneto-optic recording medium (such as a magneto-optic disk),a Compact Disc Read Only Memory (CD-ROM), CD-R, CD-R/W, and asemiconductor memory (such as a mask ROM, a Programmable ROM (PROM), anErasable PROM (EPROM), a flash ROM, and a Random Access Memory (RAM)).These programs may be supplied to computers by using various types oftransitory computer readable media. Examples of the transitory computerreadable media include an electrical signal, an optical signal, and anelectromagnetic wave. The transitory computer readable media can be usedto supply programs to a computer through a wired communication line(e.g., electric wires and optical fibers) or a wireless communicationline.

OTHER EMBODIMENTS

Each of the above embodiments may be used individually, or two or moreof the embodiments may be appropriately combined with one another.

Further, the above-described embodiments are merely examples ofapplications of the technical ideas obtained by the inventor. Thesetechnical ideas are not limited to the above-described embodiments andvarious modifications can be made thereto.

The whole or part of the embodiments disclosed above can be describedas, but not limited to, the following supplementary notes.

(Supplementary Note 1)

A control apparatus comprising:

a memory; and

at least one processor coupled to the memory and configured to execute aplurality of modules, the plurality of modules comprising:

an acquisition module configured to acquire a required end-to-endperformance required for an end-to-end path from a first end node to asecond end node, the end-to-end path including the first and second endnodes and at least one intermediate node, the end-to-end path includinga plurality of path segments;

a control module configured to determine each required segmentperformance required for a respective one of the path segments based onthe required end-to-end performance; and

an enforcement module configured to communicate with a node included ineach path segment or communicate with an entity controlling the pathsegment to enforce a corresponding one of the required segmentperformances in the path segment, and

wherein the control module is further configured to update a requiredsegment performance currently enforced in at least one path segmentbased on an achievement status of each of the required segmentperformances in the respective path segments.

(Supplementary Note 2)

The control apparatus described in Supplementary note 1, wherein thecontrol module is configured to perform one or both of:

relaxing a new required segment performance for a path segment that hasnot been able to achieve a currently enforced required segmentperformance therein; and

tightening a new required segment performance for a path segment thathas achieved a currently enforced required segment performance therein.

(Supplementary Note 3)

The control apparatus described in Supplementary note 1 or 2, whereinthe control module is configured to:

when a difference between a currently enforced required segmentperformance and a new required segment performance exceeds a threshold,enforce the new required segment performance in a corresponding one ofthe path segments through the enforcement module; and

when the difference does not exceed the threshold, refrain fromenforcing the new required segment performance.

(Supplementary Note 4)

The control apparatus described in any one of Supplementary notes 1 to3, wherein the control module is further configured to determine whethereach of the required segment performances has been achieved based on amonitored performance parameter of a respective one of the pathsegments.

(Supplementary Note 5)

The control apparatus described in any one of Supplementary notes 1 to4, wherein

at least one of the first and second end nodes is a radio terminal,

the at least one intermediate node includes a base station, and

at least one of the path segments is a radio access network segmentbetween the radio terminal and the base station.

(Supplementary Note 6)

The control apparatus described in Supplementary note 5, wherein

the first and second end nodes are the same radio terminal, and

the end-to-end path is a round-trip path.

(Supplementary Note 7)

The control apparatus described in Supplementary note 5 or 6, whereinthe enforcement module is configured to communicate with the basestation to enforce a corresponding one of the required segmentperformances in the radio access network segment.

(Supplementary Note 8)

The control apparatus described in any one of Supplementary notes 1 to7, wherein

the end-to-end performance relates to an acceptable delay for theend-to-end path, and

each of the required segment performances relates to an acceptable delayfor a respective one of the path segments.

(Supplementary Note 9)

A method performed by a control apparatus, the method comprising:

acquiring a required end-to-end performance required for an end-to-endpath from a first end node to a second end node, the end-to-end pathincluding the first and second end nodes and at least one intermediatenode, the end-to-end path including a plurality of path segments;

determining each required segment performance required for a respectiveone of the path segments based on the required end-to-end performance;

communicating with a node included in each path segment or communicatingwith an entity controlling the path segment to enforce a correspondingone of the required segment performances in the path segment; and

updating a required segment performance currently enforced in at leastone path segment based on an achievement status of each of the requiredsegment performances in the respective path segments.

(Supplementary Note 10)

The method described in Supplementary note 9, wherein the updatingcomprises one or both of:

relaxing a new required segment performance for a path segment that hasnot been able to achieve a currently enforced required segmentperformance therein; and

tightening a new required segment performance for a path segment thathas achieved a currently enforced required segment performance therein.

(Supplementary Note 11)

The method described in Supplementary note 9 or 10, wherein the updatingcomprises:

when a difference between a currently enforced required segmentperformance and a new required segment performance exceeds a threshold,enforcing the new required segment performance in a corresponding one ofthe path segments; and

when the difference does not exceed the threshold, refraining fromenforcing the new required segment performance.

(Supplementary Note 12)

The method described in any one of Supplementary notes 9 to 11, furthercomprising determining whether each of the required segment performanceshas been achieved based on a monitored performance parameter of arespective one of the path segments.

(Supplementary Note 13)

The method described in any one of Supplementary notes 9 to 12, wherein

at least one of the first and second end nodes is a radio terminal,

the at least one intermediate node includes a base station, and

at least one of the path segments is a radio access network segmentbetween the radio terminal and the base station.

(Supplementary Note 14)

The method described in Supplementary note 13, wherein the first andsecond end nodes are the same radio terminal, and the end-to-end path isa round-trip path.

(Supplementary Note 15)

The method described in Supplementary note 13 or 14, wherein theenforcing comprises communicating with the base station to enforce acorresponding one of the required segment performances in the radioaccess network segment.

(Supplementary Note 16)

The method described in any one of Supplementary notes 9 to 15, wherein

the end-to-end performance relates to an acceptable delay for theend-to-end path, and

each of the required segment performances relates to an acceptable delayfor a respective one of the path segments.

(Supplementary Note 17)

A program for causing a computer to perform a method performed by acontrol apparatus, the method comprising:

acquiring a required end-to-end performance required for an end-to-endpath from a first end node to a second end node, the end-to-end pathincluding the first and second end nodes and at least one intermediatenode, the end-to-end path including a plurality of path segments;

determining each required segment performance required for a respectiveone of the path segments based on the required end-to-end performance;

communicating with a node included in each path segment or communicatingwith an entity controlling the path segment to enforce a correspondingone of the required segment performances in the path segment, and

updating a required segment performance currently enforced in at leastone path segment based on an achievement status of each of the requiredsegment performances in the respective path segments.

REFERENCE SIGNS LIST

-   10 END NODE-   20 INTERMEDIATE NODE-   30 END NODE-   40 CONTROLLER-   702 PROCESSOR-   703 MEMORY-   704 ACQUISITION MODULE-   705 CONTROL MODULE-   706 ENFORCEMENT MODULE

The invention claimed is:
 1. A control apparatus comprising: one or morememories storing instructions; and one or more processors configured toexecute the instructions to implement: an acquisition module configuredto acquire a required end-to-end performance required for an end-to-endpath from a first end node to a second end node, the end-to-end pathincluding the first and second end nodes and at least one intermediatenode, the end-to-end path including a plurality of path segments, therequired end-to-end performance comprising both of an acceptableend-to-end delay for the end-to-end path and an end-to-end throughputtarget of the end-to-end path; a control module configured to determineeach required segment performance required for a respective one of thepath segments based on the required end-to-end performance, the requiredsegment performance comprising both of an acceptable segment delay forthe corresponding path segment and a throughput target for thecorresponding path segment; and an enforcement module configured tocommunicate with a node included in each path segment or communicatewith an entity controlling the path segment to enforce a correspondingone of the required segment performances in the path segment, whereinthe control module is configured to: identify a first path segment fromamong the plurality of path segments that has not been able to achieve acurrently enforced first path required segment performance enforced onthe first path segment; identify a second path segment from among theplurality of path segments that has been able to achieve a currentlyenforced second path required segment performance enforced on the secondpath segment; relax the currently enforced first path required segmentperformance enforced on the first path segment to a new first pathrequired segment performance to be enforced on the first path segment byincreasing the acceptable segment delay for the first path segment ordecreasing the throughput target for the first path segment; and tightenthe currently enforced second path required segment performance enforcedon the second path segment to a new second path required segmentperformance to be enforced on the second path segment by decreasing theacceptable segment delay for the second path segment or increasing thethroughput target for the second path segment.
 2. The control apparatusaccording to claim 1, wherein the control module is configured to: whena difference between a currently enforced required segment performanceand a new required segment performance exceeds a threshold, enforce thenew required segment performance in a corresponding one of the pathsegments through the enforcement module; and when the difference doesnot exceed the threshold, refrain from enforcing the new requiredsegment performance.
 3. The control apparatus according to claim 1,wherein the control module is further configured to determine whethereach of the required segment performances has been achieved based on amonitored performance parameter of a respective one of the pathsegments.
 4. The control apparatus according to claim 1, wherein atleast one of the first and second end nodes is a radio terminal, the atleast one intermediate node includes a base station, and at least one ofthe path segments is a radio access network segment between the radioterminal and the base station.
 5. The control apparatus according toclaim 4, wherein the first and second end nodes are the same radioterminal, and the end-to-end path is a round-trip path.
 6. The controlapparatus according to claim 4, wherein the enforcement module isconfigured to communicate with the base station to enforce acorresponding one of the required segment performances in the radioaccess network segment.
 7. The control apparatus according to claim 1,wherein the control module is configured to: obtain a first monitoredperformance parameter from a first intermediate node among the at leastone intermediate node; obtain a second monitored performance parameterfrom a second intermediate node among the at least one intermediatenode; and identify the first path segment that has not been able toachieve the currently enforced first path required segment performanceand the second path segment from among the plurality of path segmentsthat has been able to achieve the currently enforced second pathrequired segment performance based on the first monitored performanceparameter and the second monitored performance parameter.
 8. The controlapparatus according to claim 1, wherein the enforcement module isfurther configured to enforce the new first path required segmentperformance and the new second path required segment performance bycontrolling one or both of packet scheduling and packet queuingperformed by one of the end nodes and the at least one intermediatenode.
 9. The control apparatus according to claim 1, wherein theenforcement module is further configured to enforce the new first pathrequired segment performance and the new second path required segmentperformance by changing a delay threshold used for calculation of anEarliest Deadline First (EDF) metric for a first packet flow related tothe new first path required segment performance and a second packet flowrelated to the new second path required segment performance.
 10. Amethod performed by a control apparatus, the method comprising:acquiring a required end-to-end performance required for an end-to-endpath from a first end node to a second end node, the end-to-end pathincluding the first and second end nodes and at least one intermediatenode, the end-to-end path including a plurality of path segments, therequired end-to-end performance comprising both of an acceptableend-to-end delay for the end-to-end path and an end-to-end throughputtarget of the end-to-end path; determining each required segmentperformance required for a respective one of the path segments based onthe required end-to-end performance, the required segment performancecomprising both of an acceptable segment delay for the correspondingpath segment and a throughput target for the corresponding path segment;communicating with a node included in each path segment or communicatingwith an entity controlling the path segment to enforce a correspondingone of the required segment performances in the path segment; andidentifying a first path segment from among the plurality of pathsegments that has not been able to achieve a currently enforced firstpath required segment performance enforced on the first path segment;identifying a second path segment from among the plurality of pathsegments that has been able to achieve a currently enforced second pathrequired segment performance enforced on the second path segment;relaxing the currently enforced first path required segment performanceenforced on the first path segment to a new first path required segmentperformance to be enforced on the first path segment by increasing theacceptable segment delay for the first path segment or decreasing thethroughput target for the first path segment; and tightening thecurrently enforced second path required segment performance enforced onthe second path segment to a new second path required segmentperformance to be enforced on the second path segment by decreasing theacceptable segment delay for the second path segment or increasing thethroughput target for the second path segment.
 11. The method accordingto claim 10, wherein the updating comprises: when a difference between acurrently enforced required segment performance and a new requiredsegment performance exceeds a threshold, enforcing the new requiredsegment performance in a corresponding one of the path segments; andwhen the difference does not exceed the threshold, refraining fromenforcing the new required segment performance.
 12. The method accordingto claim 10, further comprising determining whether each of the requiredsegment performances has been achieved based on a monitored performanceparameter of a respective one of the path segments.
 13. The methodaccording to claim 10, wherein at least one of the first and second endnodes is a radio terminal, the at least one intermediate node includes abase station, and at least one of the path segments is a radio accessnetwork segment between the radio terminal and the base station.
 14. Themethod according to claim 13, wherein the first and second end nodes arethe same radio terminal, and the end-to-end path is a round-trip path.15. The method according to claim 13, wherein the enforcing comprisescommunicating with the base station to enforce a corresponding one ofthe required segment performances in the radio access network segment.16. The method according to claim 10, further comprising: obtaining afirst monitored performance parameter from a first intermediate nodeamong the at least one intermediate node; obtaining a second monitoredperformance parameter from a second intermediate node among the at leastone intermediate node; and identifying the first path segment that hasnot been able to achieve the currently enforced first path requiredsegment performance and the second path segment from among the pluralityof path segments that has been able to achieve the currently enforcedsecond path required segment performance based on the first monitoredperformance parameter and the second monitored performance parameter.17. The method according to claim 10, wherein the relaxing comprisescontrolling one or both of packet scheduling and packet queuingperformed by one of the end nodes and the at least one intermediate nodebased on the new first path required segment performance, and whereinthe tightening comprises controlling one or both of packet schedulingand packet queuing performed by one of the end nodes and the at leastone intermediate node based on the new second path required segmentperformance.
 18. A non-transitory computer readable medium storing aprogram for causing a computer to perform a method performed by acontrol apparatus, the method comprising: acquiring a requiredend-to-end performance required for an end-to-end path from a first endnode to a second end node, the end-to-end path including the first andsecond end nodes and at least one intermediate node, the end-to-end pathincluding a plurality of path segments, the required end-to-endperformance comprising both of an acceptable end-to-end delay for theend-to-end path and an end-to-end throughput target of the end-to-endpath; determining each required segment performance required for arespective one of the path segments based on the required end-to-endperformance, the required segment performance comprising both of anacceptable segment delay for the corresponding path segment and athroughput target for the corresponding path segment; communicating witha node included in each path segment or communicating with an entitycontrolling the path segment to enforce a corresponding one of therequired segment performances in the path segment, and identifying afirst path segment from among the plurality of path segments that hasnot been able to achieve a currently enforced first path requiredsegment performance enforced on the first path segment; identifying asecond path segment from among the plurality of path segments that hasbeen able to achieve a currently enforced second path required segmentperformance enforced on the second path segment; relaxing the currentlyenforced first path required segment performance enforced on the firstpath segment to a new first path required segment performance to beenforced on the first path segment by increasing the acceptable segmentdelay for the first path segment or decreasing the throughput target forthe first path segment; and tightening the currently enforced secondpath required segment performance enforced on the second path segment toa new second path required segment performance to be enforced on thesecond path segment by decreasing the acceptable segment delay for thesecond path segment or increasing the throughput target for the secondpath segment.
 19. The non-transitory computer readable medium accordingto claim 18, wherein the relaxing comprises controlling one or both ofpacket scheduling and packet queuing performed by one of the end nodesand the at least one intermediate node based on the new first pathrequired segment performance, and wherein the tightening comprisescontrolling one or both of packet scheduling and packet queuingperformed by one of the end nodes and the at least one intermediate nodebased on the new second path required segment performance.